Browsing by Author "Marsal, L F"

Now showing items 1-20 of 20

    • Analysis of bias stress on thin-film transistors obtained by Hot-Wire Chemical Vapour Deposition 

      Dosev, D K; Puigdollers i González, Joaquim; Orpella García, Alberto; Voz Sánchez, Cristóbal; Fonrodona, Marta; Soler Vilamitjana, David; Marsal, L F; Pallarès Marzal, Josep; Bertomeu Balaguero, Joan; Andreu Batallé, Jordi; Alcubilla González, Ramón (2001-02)
      Article
      Open Access
      The stability under gate bias stress of unpassivated thin film transistors was studied by measuring the transfer and output characteristics at different temperatures. The active layer of these devices consisted of in ...

    • Analysis of conduction mechanisms in annealed n-Si1-xCx:H/p-crystalline Si heterojunction diodes for different doping concentrations 

      Marsal, L F; Pallares, J; Correig, X; Orpella García, Alberto; Bardés Llorensí, Daniel; Alcubilla González, Ramón (American Institute of Physics (AIP), 1999-01)
      Article
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      We fabricated and characterized annealed n-type amorphous Si1-xCx on p-type crystalline silicon heterojunction diodes with three different base doping concentrations: NA~1016,¿1018, and 1020¿cm-3. The conduction mechanisms ...

    • Analysis of photonic band gaps in two-dimensional photonic crystals with rods covered by a thin interfacial layer 

      Todorov Trifonov, Trifon; Marsal, L F; Rodríguez Martínez, Ángel; Pallarès Marzal, Josep; Alcubilla González, Ramón (2004-11)
      Article
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      We investigate different aspects of the absolute photonic band gap (PBG) formation in two-dimensional photonic structures consisting of rods covered with a thin dielectric film. Specifically, triangular and honeycomb ...

    • Characterization and application of a-SiCx:H films for the passivation of the c-Si surface 

      Martín Campos, Ignacio Clemente; Vetter, M; Orpella García, Alberto; Puigdollers i González, Joaquim; Voz Sánchez, Cristóbal; Marsal, L F; Pallarès Marzal, Josep; Alcubilla González, Ramón (2002-01)
      Article
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      In this work we investigate the effects of typical thermal treatments on c-Si surface passivation by intrinsic a-SiCx:H films. First, a forming gas anneal (FGA), (400 °C, 30 min in H2/N2) is applied resulting in an improvement ...

    • Characterization of 2D macroporous silicon photonic crystals: improving the photonic band identification in angular-dependent reflection spectroscopy in the mid-IR 

      Král, Z; Ferré Burrull, José; Pallarès Marzal, Josep; Todorov Trifonov, Trifon; Rodríguez Martínez, Ángel; Alcubilla González, Ramón; Marsal, L F (2008-02)
      Article
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      We report the experimental characterization of two-dimensional (2D) macroporous silicon photonic crystals using angular-dependent reflectance spectroscopy in the mid-IR region. We have investigated different sample structures ...

    • Distribution of recombination currents in the space charge of heterostructure bipolar devices 

      Pallares, J; Marsal, L F; Correig, X; Calderer Cardona, Josep; Alcubilla González, Ramón (1998-01)
      Article
      Open Access
      This paper addresses the problem of the space charge region Shockley-Read-Hall (SRH) recombination currents in heterojunctions with one noncrystalline side. A formulation which generalizes previous works is discussed. The ...

    • Effects of symmetry reduction in two-dimensional square and triangular lattices 

      Todorov Trifonov, Trifon; Marsal, L F; Rodríguez Martínez, Ángel; Pallarès Marzal, Josep; Alcubilla González, Ramón (2004-06)
      Article
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      We investigate the absolute photonic band gap (PBG) formation in two-dimensional (2-D) photonic crystals designed using symmetry reduction approach. The lattice symmetry, shape and orientation of dielectric scatterers ...

    • Fabrication and characterization of in-situ doped a-Si0.8C0.2 emitter bipolar transistors 

      Orpella García, Alberto; Puigdollers i González, Joaquim; Bardés Llorensí, Daniel; Alcubilla González, Ramón; Marsal, L F; Pallarès Marzal, Josep (2000-09)
      Article
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      Silicon–carbon emitters were deposited by plasma enhanced chemical vapour deposition (PECVD) on a conventional silicon transistor base. The resulting transistors were annealed after the emitter had been deposited which led ...

    • Fabrication of silicon oxide microneedles from macroporous silicon 

      Rodríguez Martínez, Ángel; Molinero, D; Valera Cano, Enrique Andrés; Todorov Trifonov, Trifon; Marsal, L F; Pallarès Marzal, Josep; Alcubilla González, Ramón (2005-04)
      Article
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      This paper presents a novel technique for silicon dioxide (SiO2) microneedle fabrication. Microneedles are hollow microcapillaries with tip diameters in the range of micrometers. They can be used in the fabrication of ...

    • Fabrication of two- and three-dimensional photonic crystals by electrochemical etching of silicon 

      Todorov Trifonov, Trifon; Marsal, L F; Rodríguez Martínez, Ángel; Pallarès Marzal, Josep; Alcubilla González, Ramón (2005-05)
      Article
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      This paper reports on the fabrication of two-dimensional macropore arrays by electrochemical etching of silicon. We describe some critical effects accompanying the etching process that can generate imperfections in the ...

    • High aspect ratio silicon dioxide pillars 

      Todorov Trifonov, Trifon; Rodríguez Martínez, Ángel; Servera, F; Marsal, L F; Pallarès Marzal, Josep; Alcubilla González, Ramón (2005-06)
      Article
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      This article describes the benefits of including cross-layer information in the scheduling mechanism of a UMTS downlink channel. In particular, the information obtained from the fast power control algorithm is used to ...

    • In-situ doped amorphous Si0.8C0.2 emitter bipolar transistors 

      Orpella García, Alberto; Bardés Llorensí, Daniel; Alcubilla González, Ramón; Marsal, L F; Pallarès Marzal, Josep (1999-11)
      Article
      Open Access
      The fabrication and characterization of in situ-doped amorphous Si/sub 0.8/C/sub 0.2/ emitter transistors are presented. Emitter Gummel numbers exceeding 10/sup 14/ s/cm/sup 4/ are reported for the first time in this type ...

    • Investigation of the formation of silicon nanocrystals by annealing of amorphous SiCx/c-Si structures 

      Torres, I; Vetter, M; Ferré Burrull, José; Marsal, L F; Orpella García, Alberto; Alcubilla González, Ramón; Pallarès Marzal, Josep (2007-04)
      Article
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      In this work, we study the changes in the optical properties of 300-nm-thick hydrogenated amorphous silicon carbide layers after an annealing process. Both intrinsic and phosphorus-doped amorphous silicon carbide layers ...

    • Larger absolute photonic bandgap in two-dimensional air-silicon structures 

      Marsal, L F; Todorov Trifonov, Trifon; Rodríguez Martínez, Ángel; Pallarés, J; Alcubilla González, Ramón (2003-05)
      Article
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      We investigate different aspects of the absolute photonic band gap (PBG) formation for two-dimensional photonic crystals, consisting of air rods drilled into silicon. Specifically, square lattices of square and circular ...

    • Macroporous silicon: a versatile material for 3D structure fabrication 

      Todorov Trifonov, Trifon; Rodríguez Martínez, Ángel; Marsal, L F; Pallares, J; Alcubilla González, Ramón (2008-02)
      Article
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      This work focuses on the fabrication of three-dimensional (3D) microstructures by electrochemical etching of n-type silicon. We exploit the possibility of modulating the pore diameter along the growing direction to produce ...

    • Microcrystalline silicon thin film transistors obtained by hot-wire CVD 

      Puigdollers i González, Joaquim; Dosev, D; Orpella García, Alberto; Voz Sánchez, Cristóbal; Peiro, D; Bertomeu Balaguero, Joan; Marsal, L F; Pallarés, J; Andreu Batallé, Jordi; Alcubilla González, Ramón (1999-12)
      Article
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      Polysilicon thin film transistors (TFT) are of great interest in the field of large area microelectronics, especially because of their application as active elements in flat panel displays. Different deposition techniques ...

    • New approaches for the fabrication of photonic structures of nonlinear optical materials 

      Carvajal, J J; Peña, A; Kumar, R.; Pujol, M. C.; Mateos, X.; Aguiló Díaz, Magdalena; Díaz, F; Vázquez De Aldana, J. R.; Méndez, Carlos Alberto; Moreno, P; Roso, L; Todorov Trifonov, Trifon; Rodríguez Martínez, Ángel; Alcubilla González, Ramón; Král, Z; Ferré Borrull, J.; Pallarès Marzal, Josep; Marsal, L F; Finizio, Sergio Di; Martorell Pena, Jordi; Macovez, Roberto (2009-12)
      Article
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      We revisited two different strategies to fabricate 1D photonic crystals of nonlinear optical dielectric materials based on ultrafast laser ablation of the surface of an RbTiOPO4 crystal, and selective etching of ferroelectric ...

    • Semiconducting P3HT microstructures: fibres and tubes obtained from macroporous silicon template 

      Palacios, R; Formentin, P; Todorov Trifonov, Trifon; Estrada del Cueto, Magali; Alcubilla González, Ramón; Pallares, J; Marsal, L F (2008-10)
      Article
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      Microtubes and microfibres composed of poly(3-hexylthiophene) (P3HT) were fabricated by melt-assisted templates using ordered macroporous silicon. We have studied the influence of the pore depth and the template type on ...

    • Thin film transistors obtained by hot wire CVD 

      Puigdollers i González, Joaquim; Orpella García, Alberto; Dosev, D; Voz Sánchez, Cristóbal; Peiró, D; Pallarés, J; Marsal, L F; Bertomeu Balaguero, Joan; Andreu Batallé, Jordi; Alcubilla González, Ramón (2000-05)
      Article
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      Hydrogenated microcrystalline silicon films obtained at low temperature (150–280°C) by hot wire chemical vapour deposition at two different process pressures were measured by Raman spectroscopy, X-ray diffraction (XRD) ...

    • Tuning the shape of macroporous silicon 

      Todorov Trifonov, Trifon; Garin Escriva, Moises; Rodríguez Martínez, Ángel; Marsal, L F; Alcubilla González, Ramón (2007-10)
      Article
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      Macroporous silicon membranes, prepared by photo-electrochemical etching, were subjected to pore widening performed by multiple oxidation/oxide-stripping cycles. We study the dependence of pore cross section and diameter ...